看到他笑，我忍不住也笑了。
kàndào tā xiào ， wǒ rěnbùzhù yě xiàole 。
Seeing him smile, I couldn't help but laugh too.
这部电影太感人，我忍不住哭了。
zhè bù diànyǐng tài gǎnrén ， wǒ rěnbùzhù kūle 。
This movie is so touching that I couldn't help but cry.
他一说话，我忍不住想笑。
tā yī shuōhuà ， wǒ rěnbùzhù xiǎngxiào 。
As soon as he spoke, I couldn't help but want to laugh.